In view of the serious nature of the current AIDS epidemic, there exists a considerable need for the development of more sensitive and efficient methods for measuring the viral infection. The Laboratory of Retroviral Biology (LRB) is currently involved in a number of studies relating to the characterization of the immune response against HIV, and the development of drugs and vaccines against this virus. For these studies, a new fluorescent focus assay has been developed which can routinely measure viral antigen expressed in a singly round of infection. This has led to a rapid (24 hour) assay for quantitating I-UV infection, which is presently being used to measure neutralizing titers of human sera, human and chimp monoclonal antibodies against the virus, and antiviral drugs. However, a major limitation which has prevented the wide-spread adaptation of this assay, and its potential commercial application, has been the difficulty in standardizing and automating the data accumulation aspects of this assay. In the present proposal, a collaboration is proposed between the LRB and Cellvision, a new company developing products in the area of image analysis, to develop and apply efficient, state-of-the-art methods towards the standardization and automation of the new HIV infectivity assay. It is anticipated that this collaboration will lead to the broad application of this assay to problems of interest in the area of AIDS research, and may also have broader applications in